Substrate processing method and substrate processing device

ABSTRACT

A processing tank  10  is divided into a washing section  15  and a drying section  30 , a clearance is formed in the joint between the sections, and the clearance is communicated with by sink  29 . In drying a substrate, the substrate is moved from the washing section to the drying section, a porous plate  28  is inserted into the lower region where the clearance is formed, and a drying gas is jetted against the substrate with the internal pressure of the drying section  30  kept higher than that of the sink  29  and the internal pressure of the washing section  15  kept lower than that of the drying section  30 . In this case, it is preferable that the porous plate  28  is a punched plate in which plural small holes having predetermined diameters have been made. The above configuration provides a substrate processing method and a substrate processing device in which the drying gas can uniformly and stably be supplied to an assembly of plural substrates.

TECHNICAL FIELD

The present invention relates to a substrate processing method and asubstrate processing device, which can perform processing on asemiconductor wafer, a liquid crystal display device substrate, arecording disk substrate, a mask substrate, and other substrates, inparticular it is a substrate processing method and substrate processingdevice which can perform within one processing tank a series of surfaceprocesses from the processing of various substrates with a chemicalsolution to the process of drying the substrates.

BACKGROUND ART

In the semiconductor production process, for various substrates, forexample in order to clean a wafer surface, after the wafer surface iscleansed with a chemical solution, washing is performed using aprocessing solution such as pure water, and the wafer is dried with anorganic solvent such as isopropyl alcohol (hereinafter referred to asIPA). More specifically, the processes includes a process, in which,after the wafer is cleansed with the chemical solution and pure water,the wafer is exposed in an IPA vapor to condense IPA on the wafersurface, thus substituting IPA for the pure water adhering to the wafer,and contaminants such as particles are washed from the wafer surface byrunning pure water down the wafer surface, and a drying process ofvaporizing IPA to dry the wafer surface. In the drying process, if evena small droplet of water remains on the wafer surface, a water mark isformed on the wafer surface, which causes wafer quality to be worsenedin the same way as a particle does. Therefore, in the semiconductorproduction process, it is necessary that such contaminants do not adhereto the wafer. Many methods and apparatus for processing the substratesurface of the wafer, in which measures are taken against contaminants,have been devised and put into practical use. Such methods and apparatusfor processing the substrate are disclosed in many patent documents suchas Japanese Patent Laid-Open No. 2001-271188 (see FIG. 1 and rightcolumn of page 5 to left column of page 6).

The substrate processing device described in Japanese Patent Laid-OpenNo. 2001-271188 includes one processing tank. The processing tankincludes a bottomed box body and a lid. The box body has an open upperregion. The opening of the box body is covered with the lid. The openingof the box body is formed to a size such that the many wafers can besupported and accommodated at predetermined intervals and in paralleland vertical orientation. The depth of the box body is formed to suchextent that the upper space has an appropriate volume in which it isensured an inert gas can be supplied when the wafers are dipped into it.The processes including the chemical-solution process, the process ofwashing out the chemical solution from the wafer surface using purewater, and the drying process of removing the water adhering to andremaining on the wafer surface with mixed substitution of the organicsolvent vapor and the inert gas after the washing process is performedin the one processing tank.

When the flow of the inert gas within the processing tank wasinvestigated during the wafer drying process, routes shown in FIG. 9were observed. FIG. 9 is a sectional view schematically showing the flowof the inert gas within the processing tank. Substrate processing device1 includes a processing tank 2 with an inner tank 2 ₁, an outer tank 2₂, and a lid 2 ₃. The outer tank 2 ₂ has a bottomed box shape and anopen upper region. The inner tank 2 ₁ surrounds the outer periphery inthe upper region of the inner tank 2 ₁. An openable and closable lid 2 ₃is provided in the upper region of the outer tank. A processing solutiondischarge hole 2 ₁₂ is made in a bottom region of the inner tank 2 ₁.One end of the exhaust pipe 5 is connected to the processing solutiondischarge hole 2 ₁₂, and the other end of the exhaust pipe 5 is coupledto a vacuum pump or the like. Vapor ejection ports 8 are protruded inthe outer tank 2 ₂, and the vapor ejection ports 8 are coupled to avapor supply mechanism 9. Gas jet nozzles 4 ₁ are mounted in the upperregion of the lid 2 ₃, and the gas jet nozzles 4 ₁ are connected to anitrogen gas supply source 7 through piping 4.

In the substrate processing device 1, when the nitrogen gas N₂ (dryinggas) from the nitrogen gas supply source 7 is jetted from the upperregion of the processing tank 2, the jetted nitrogen gas N₂ flowsdownward, and the nitrogen gas N₂ is jetted onto an assembly of wafersW′, and the nitrogen gas N₂ is exhausted outside the tank from anexhaust pipe 5. At this point, some of the jet gas is exhausted outsidethe sink 3 through the space between the outer tank 2 ₂ and the lid 2 ₃.The outside of the sink 3 is at atmospheric pressure. As shown by arrowsin FIG. 9, the gas jetted onto the assembly of wafers W′ collides withthe bottom wall surface of the inner tank 2 ₁ and rises to circulate inthe processing tank 2, and then the gas is exhausted from the exhaustpipe 5. The surfaces of the assembly of wafers W′ are dried by the gasdirectly jetted from the jet nozzles 4 i and by the gas circulating theinside of the processing tank 2.

DISCLOSURE OF THE INVENTION

However, in the substrate processing device described in Japanese PatentLaid-Open No. 2001-271188, since some of the drying gas is exhaustedfrom the exhaust pipe while circulating the inside of the processingtank, the flow of the drying gas is not kept constant in the processingtank, and the flow of the drying gas becomes turbulent. As a result, thenitrogen gas is not uniformly supplied to individual wafers generatingunevenness in the processing of the substrate surface. The turbulentstate increases as the amount of drying gas is increased, which enlargesthe unevenness of the processing. Therefore, stable surface processingcannot be performed. Further, since only one processing solutiondischarge hole is made in the bottom region of the inner tank, it isfound that the turbulence becomes violent in the tank when the flow rateof the drying gas is increased, e.g., when the flow rate becomes about100 L/min. It is believed that one of the causes of the turbulence isthat the processing tank is not divided into a drying section and awashing section.

On the other hand, when the exhaust processing facility to which theexhaust pipe is connected was investigated, it was found that the causeof the turbulence is also attributed to the exhaust processing facility.Usually the exhaust pipe from the substrate processing device isconnected to the exhaust processing facility. In the exhaust processingfacility, a vacuum pump is used, and plural instruments and devices areconnected to the pump to manage the exhaust processing in a collectivemanner. Therefore, it is difficult to finely adjust the instruments anddevices individually in consideration of the requirements of each of theinstrument and device, and facility cost is increased when individualadjustment is performed for each instrument and device. Further, in theusual exhaust processing facility, fluctuation in pressure of theevacuating station becomes intense during the initial stage of start-upor during stopping the exhaust processing facility. Therefore, in orderto process a large amount of wafers while maintaining high quality, itis necessary to minimize the influence of the evacuating station in theexhaust processing facility. However, in the substrate processing devicedescribed in Japanese Patent Laid-Open No. 2001-271188, it is verydifficult to perform this adjustment.

Recently, for the wafers processed by this kind of substrate processingdevice, in order to increase processing efficiency, it is necessary thatas many wafers as possible are inserted into the processing tank whilebeing held by a lifting mechanism. In some cases, the wafers aresimultaneously processed in the processing tank in lot units rangingfrom 50 to 100 wafers, and the distance between the substrates tends tobe narrowed to as small as several millimeters because the substratesare supported in a parallel and vertical orientation. Thus, when a largeamount of substrates are processed with the chemical solutions in theprocessing tank, or when the rinsing process is performed on a largeamount of substrate using pure water, it is necessary that theprocessing solution is supplied to the inside of the processing tankwhile the large amount of substrate is inserted in the processing tank,or it is necessary that the processing solution is substituted foranother processing solution while the large amount of substrate isinserted in the processing tank. At this point, processing speeds on thesubstrates fluctuate and a long time is required for drying, so thatthere is the problem that particles and the like are easily generated.

In view of the foregoing, the invention is particularly to solve theproblem in the drying process in the conventional art, and the firstobject of the invention is to provide a substrate processing methodwhich can uniformly and stably supply the drying gas to the assembly ofplural substrates.

The second object of the invention is to provide a substrate processingdevice which decreases contaminants adhering to the substrate surfaceand prevents a decrease in yield caused by contamination when a largeamount of substrates is processed.

The above objects can be achieved by the following means. That is, thesubstrate processing method of the invention is characterized byincluding: dividing a processing tank into a washing section and adrying section; forming a clearance in the joint between the washingsection and the drying section; communicating the clearance with a sink;moving the substrate from the washing section to the drying section whendrying the substrate; inserting a porous plate into the lower regionwhere the clearance is formed; and jetting a drying gas against thesubstrate with the internal pressure of the drying section kept higherthan that of the sink and the internal pressure of the washing sectionkept lower than that of the drying section. According to the substrateprocessing method, in drying the substrate, after the drying gas issupplied to a group of substrates in the drying section, some of thedrying gas flows to the sink through the clearance, and the remainder ofthe drying gas is exhausted to the outside through the washing section.At this point, since the internal pressure of the drying section issecurely higher than that of the drying section, the down-flow of thedrying gas becomes smooth in the washing section, which allows thesurface processing of the group of plural substrates to be efficientlyperformed by the laminar flow of the drying gas.

The substrate processing method of the invention is characterized inthat a processing solution supply unit and a processing solutiondischarge unit are independently provided in the bottom region of thewashing section, and the following processes (a) to (d) are performed inwashing the substrate: (a) a process of supplying a chemical solutionfrom the processing solution supply unit into the processing tank toreserve the chemical solution in the processing tank, (b) a process ofinputting and dipping the substrate in the processing tank to performchemical-solution processing on the substrate for a predetermined time;(c) a process of supplying a washing solution from the processingsolution supply unit after the chemical-solution processing is finished,and of discharging the chemical solution from the processing tankthrough the processing solution discharge unit; and (d) a process ofstopping the supply of the washing solution after the chemical solutionhas been discharged.

According to the substrate processing method, since the series ofprocesses such as the chemical-solution process, the washing process,and the drying process can be performed in the same processing tank, thesubstrate is never exposed to the air during the series of processes.Accordingly, the efficiency of the substrate processing is improved, theformation of a natural oxide film can be suppressed, and thecontamination caused by particles can be prevented.

It is preferable that a drain mechanism is provided in the processingsolution discharge unit and, in drying the substrate, the processingsolution in the washing section is discharged for a short time byoperating the drain mechanism at the same time as when the porous plateis inserted between the washing section and the drying section. It isalso preferable that the porous plate is a punched plate in which pluralsmall holes of a predetermined diameter have been punched.

According to the substrate processing method, while the drying gas isdispersed by the small holes of the punched plate, the internal pressureof the drying section can securely become higher than that of thewashing section. The large amount of processing solution in the washingsection is rapidly discharged by the operation of the drain mechanism,which smoothes the down-flow of the drying gas in the drying section.Therefore, surface processing of the group of plural substrates canefficiently be performed by the laminar flow of the drying gas.

The substrate processing device of the invention which includes supportmeans for supporting plural substrates to be processed at equal pitchesin parallel and vertical orientation; a washing processing tank whichaccommodates an assembly of substrates supported by the support means;and a lid with which the upper opening of the washing processing tank iscovered, the lid also functioning as a drying processing tank, thesubstrate processing device is characterized in that the lid includes acontainer having a size in which the assembly of substrates can beaccommodated, the top surface of the container being closed and a lowerregion of the container being opened, plural jet nozzles are arranged ina matrix shape at substantially equal intervals in the top surface ofthe container while respective jet-nozzle holes are orientated towardthe assembly of substrates, and, when the upper opening of the washingprocessing tank is covered with the lid, the clearance communicated withthe sink is formed between the washing processing tank and the lid, andthe porous plate is inserted into the lower region of the clearance.

According to the substrate processing device, in drying the substrate,after the drying gas has been supplied to a group of the pluralsubstrates in the drying processing tank, some of the drying gas flowsto the sink through the clearance, and the remaining gas is exhausted tothe outside through the washing processing tank. At this point, sincethe internal pressure of the drying processing tank is securely higherthan that of the washing section, the down-flow of the drying gasbecomes smooth in the drying processing tank, which allows the surfaceprocessing of the group of plural substrates to be efficiently performedby the laminar flow of the drying gas.

It is preferable that the washing processing tank includes a processingsolution discharge unit and a processing solution supply unit which areindependently provided in the bottom region of the washing processingtank; processing solution supply system piping which is connected to theprocessing solution supply unit to supply a processing solution to theprocessing tank; a chemical solution supply source which supplies thechemical solution to the processing solution supply system piping;washing solution supply means for supplying a washing solution to theprocessing tank through the processing solution supply system piping,the washing solution supply means for washing the substrate by causingthe washing solution to overflow from the upper region of the processingtank; and discharge piping which is connected to the processing solutiondischarge unit to introduce the washing solution, discharged from theprocessing tank, to the outside of the processing tank.

Due to the construction of the substrate processing device, since theseries of processes such as the chemical-solution process, the washingprocess, and the drying process can be performed in the same processingtank, the substrate is never exposed to the air during the series ofprocesses. Accordingly, the efficiency of the substrate processing isimproved, the formation of the natural oxide film can be suppressed, andthe contamination caused by the particles can be prevented.

It is preferable that a drain mechanism is provided in the processingsolution discharge unit and, in drying the assembly of substrates, thedrain mechanism is operated at the same time as the porous plate isinserted between the washing processing tank and the lid. It ispreferable that the plural jet nozzles are positioned in the top surfaceof the container along the outer circumference of the assembly ofsubstrates such that distances between the outer circumference andrespective nozzle holes become substantially equal to one another. It ispreferable that the porous plate includes a punched plate with pluralholes of a predetermined diameter.

Due to the substrate processing device, the drying gas can uniformly andstably be supplied to an assembly of substrates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing the substrate processing device inaccordance with the embodiment of the invention;

FIG. 2 is a side view showing the processing tank;

FIG. 3 is a side view showing the processing tank of FIG. 2 when viewedfrom the other side;

FIG. 4 is a perspective plan view showing the lid when viewed from anupper side;

FIG. 5 is a side view of the lid shown in FIG. 4;

FIG. 6 is a table showing the timing chart for the steps in theprocesses;

FIG. 7 shows the washing and drying process, FIG. 7(a) is a sectionalview explaining the washing process, FIG. 7(b) is a sectional viewexplaining a drying process 1, FIG. 7(c) is a sectional view explainingthe drying process 2, and FIG. 7(d) is a sectional view explaining thedrying process 3;

FIG. 8 is a sectional view schematically showing a flow for the dryinggas in FIG. 7(c); and

FIG. 9 is a sectional view showing the flow of the inert gas in theprocessing tank in the conventional substrate processing device.

BEST MODE FOR CARRYING OUT THE INVENTION

The preferred embodiment of the invention will be described below withreference to the drawings. The invention is not limited to the modeillustrated in the drawings.

Referring to FIG. 1, the substrate processing device 10 is a facilityfor processing the semiconductor wafer W which is of an example ofpossible substrates. The term of processing shall include the process ofetching the wafer W with the chemical solution, the process of applyinghydrofluoric acid treatment to the surface of the wafer W, the rinsingprocess of washing the wafer W, the drying process of drying thepost-washed wafer W with the organic solvent, and the like. This seriesof processes is continuously performed in one processing tank 15.

As shown in FIGS. 2 to 5, the processing tank 15 is placed in a housingchamber 11 which has a volume such that the processing tank 15 andaccessories thereof can be accommodated. These accessories include anair conditioning device which performs air conditioning in theaccommodation chamber, a supply source which supplies various processingsolutions to the processing tank, and a wafer conveying mechanism. Theaccessories are omitted in the drawings. The processing tank 15 includesan inner tank 20, an outer tank 25, and a lid 30. The inner tank 20 isformed in a bottomed box shape, and the upper surface of the inner tank20 is open. The outer tank 25 surrounds the upper outer periphery of theinner tank 20. The opening of the inner tank 20 is covered with the lid30. The inner and outer tanks 20 and 25 are accommodated in a sink 29.The inner and outer tanks 20 and 25 are made of a material which iscorrosion-resistant to the organic solvent such as hydrofluoric acid andIPA, e.g. made from polyvinylidene fluoride or the like.

The inner tank 20 has a depth in which the processing can be performedby dipping a large number of wafers W with a large diameter, e.g., about50 wafers W with a diameter of 300 mm in the processing solution whilebeing held by a substrate holder 62. The processing solution dischargeunit 21 and a processing solution supply unit 22 are provided in thebottom region of the inner tank 20. In the substrate holder 62, theplural wafers W are held by, e.g., a cassette guide at equal pitches andin parallel and vertical orientation. The substrate holder (cassetteguide) 62 is coupled to a lifting mechanism 60. The lifting means 61 isprovided in the lifting mechanism 60, and the cassette guide 62 is takenout from and put into the inner tank 20 by vertically moving thecassette guide 62 with the lifting means 61. The position of the dryingprocess is indicated by “Dry Position” of FIG. 2, and the position ofthe washing process is indicated by “Rinse Position.” For example, anair cylinder mechanism can be used as the lifting means 61.

The assembly of wafers is taken out from the cassette guide 62 by themoving mechanism 50. The moving mechanism 50 includes plural holdingpawls 50 ₁ and 50 ₂ coupled to a robot mechanism (not shown), and theassembly of wafers is held and moved to a predetermined position by theholding pawls 50 ₁ and 50 ₂. As shown in FIG. 2, the processing solutiondischarge unit 21 includes an outlet 21 ₁ with a small diameter and anoutlet 21 ₂ with a large diameter. The outlet 21 ₂ having the largediameter functions as a drain mechanism which rapidly discharges theprocessing solution in the processing tank. The outlet 21 ₁ having thesmall diameter discharges the processing solution reserved in the bottomregion of the inner tank 20 and in the piping. The outer tank 25functions as an overflow tank which receives the processing solutionoverflowing from the upper region of the inner tank 20. An outlet 25 ₁is provided at a lower position of the outer tank 25.

As shown in FIG. 5, the lid 30 includes a box-shaped container 31. Inthe box-shaped container 31, the lower region is opened and the upperregion is closed. An assembly of wafers W′ in which many wafers W arecollected can be housed in the box-shaped container 31. The box-shapedcontainer 31 is made of the material that is corrosion-resistant to theorganic solvent such as hydrofluoric acid and IPA. The lid 30 can bemoved horizontally by moving means 55 (see FIG. 3). The moving means 55can close and open the opening of the inner tank 20 by horizontallymoving the lid 30 above the inner tank 20 as shown by the arrow in FIG.2. That is, the moving means 55 vertically lifts up the lid 30 locatedon the inner tank 20 by a predetermined distance, the moving means 55horizontally moves the lid 30, and then the moving means 55 verticallylowers the lid 30 to hold the lid 30 in the standby state. The lid 30 ismoved when the assembly of wafers W′ is conveyed into the inner tank 20or when the assembly of wafers which is already processed is taken outfrom the inner tank 20.

As shown in FIG. 5, the top surface 32 which basically has an arch shapeis formed in the upper region of the box-shaped container 31. In the topsurface 32, plural jet nozzles 33 ₁ to 33 ₇ which jet the inert gas arearranged in four directions at substantially equal intervals. As shownin FIG. 4, in the plural nozzles 33 located above the assembly of wafersW′, the plural jet nozzles 33 ₁ to 33 ₇ are arranged in a verticalcolumn at substantially equal intervals, and the plural jet nozzles 33 ₁to 33 ₇ are also arranged in a horizontal row at substantially equalintervals. Referring to FIG. 4, the six rows of the jet nozzles, inwhich the seven jet nozzles 33 ₁ to 33 ₇ are arranged in the columndirection, are arranged in the row direction, and the 42 jet nozzles 33₁ to 33 ₈₆ are arranged in an outer circumference in the upper region ofthe assembly of wafers W′. As shown in FIG. 5, the seven jet nozzles 33₁ to 33 ₇ in the vertical column and, the jet nozzles 33 ₁ to 33 ₇ inthe top surface 32 are arranged in relation to the assembly of wafers W′such that distances between the jet nozzles 33 ₁ to 33 ₇ and the outercircumferences of the assembly of wafers W′ are equal to one another.Because the wafer W is basically formed in a circle, the distances caneasily be equalized by making the top surface 32 arch shaped. It ispreferable that the shape of the top surface is changed to substantiallyequalize the distances according to the shape of the wafer W.

The gas supply pipe 34 ₂ is connected to each respective jet nozzle 33,and the gas supply pipe 34 ₂ is branched into branch pipes 34 ₂₁ and 34₂₂. The same number of jet nozzles 33 or the substantially similarnumber of jet nozzles 33 is connected to each of the branch pipes 34 ₂₁and 34 ₂₂. Therefore, the gas can substantially be uniformly distributedto each jet nozzle. Each respective jet nozzle in which the jet gas isdiffused at a predetermined angle is used as the jet nozzle 33. When thegas is injected from each respective jet nozzle 33 to the outercircumference of the assembly of wafers, it is preferable that the jetnozzles 33 are set such that they inject gas between the adjacent jetnozzles, e.g., the gas jetted from the jet nozzle 33 ₂ and the gasjetted from the jet nozzle 33 ₃ overlap each other in the outercircumference b of the assembly of wafers. The plural jet nozzles 33 arearrayed in the top surface 32, which allows the gas to substantially beuniformly supplied to the assembly of wafers W.

As shown in FIGS. 2, 3, and 5, the intermediate connecting member 26 andthe porous plate inserting mechanism 27 are arranged between the innerand outer tanks 20 and 25 and the lid 30. The intermediate connectingmember 26 is formed of a cylindrical body whose opening has the samesize as the lower opening of the lid 30. The cylindrical body is made ofa material which is corrosion-resistant to the organic solvent such ashydrofluoric acid and IPA. The intermediate connecting member 26 ispositioned above the porous plate inserting mechanism 27. In theintermediate connecting member 26, the lower opening 26 ₂ is positionedso as to substantially abut on the upper surface of the frame body 27 ₁in which the porous plate 28 is housed, and an upper opening 26 ₁ isfitted in the lower opening 31 ₁ of the box-shaped container 31. Theintermediate connecting member 26 may be omitted by directly fitting thelid 30 in the frame body 27 ₁.

The porous plate 28 includes a flat plate in which plural small holeshave been made in the plate surface. The flat plate is inserted betweenthe inner and outer tanks 20 and 25 and the intermediate connectingmember 26 in the process of drying the assembly of wafers W′ after thepredetermined processes are finished. The porous plate is made of amaterial which is corrosion-resistant to the organic solvent such ashydrofluoric acid and IPA. The porous plate 28 is housed in the framebody 27 ₁. The porous plate 28 is coupled to the moving mechanism (notshown) and horizontally moved in a sliding manner as shown in FIG. 2.The frame body 27 ₁ housing the porous plate 28 has a predeterminedlongitudinal width (vertical direction), and a clearance 27 ₂ is madebetween the frame body 27 ₁ and the porous plate 28 when the porousplate 28 is housed in the frame body 27 ₁.

For example, the clearance 27 ₂ is about 2 mm. In the drying process,some of the dry gas is emitted into the sink 29. Therefore, since aclearance x is formed between the inner tank 20 and the lid 30(clearance is expressed by x in FIG. 8), a half-closed state is formedbetween the inner tank 20 and the lid 30 by the clearance x, i.e., thehalf-closed state is formed between the drying section and the washingsection. The porous plate 28 is inserted between the inner and outertanks 20 and 25 and the intermediate connecting member 26 to divide theinner tank from the lid, namely, the porous plate 28 functions as ashutter which partitions the processing tank 10 into a washing sectionand a drying section.

Now the piping connection between the processing tank and accessorieswill be described with reference to FIG. 1. A pipe 22 ₁ carrying theprocessing solution is connected to the processing solution supply unit22 positioned in the bottom region of the inner tank 20. The pipe 22 ₁carrying the processing solution is connected to a pure water supplysource 38 through a flow control valve and a pump. The pipe 22 ₁carrying the processing solution has the function of supplying theprocessing-solution, and the washing solution supply means includes thispiping, the flow control valve, and the pump. A chemical solution supplysource 39 is also connected to the processing solution introducing pipe22 ₁ through the flow control valve. The chemical solution supply source39 includes a chemical preparation means (not shown) for preparing thedesired chemical solution to a predetermined concentration and at apredetermined temperature. According to the purpose of the processing(for example, washing, etching, and oxidation), for example, thechemical solution can be selected from among hydrofluoric acid,hydrochloric acid, hydrogen peroxide solution, sulfuric acid, ozonewater, ammonia water, surfactant, amine organic solvent, fluorineorganic solvent, deionized water, etc. The solution in which the aboveplural chemical solutions are mixed is used as needed.

As shown in FIG. 2, the processing solution discharge unit 21 providedin the bottom region of the inner tank 20 includes the outlet 21 ₁ whichhas a small diameter and the outlet 21 ₂ which has a large diameter. Theoutlet 21 ₁ and the outlet 21 ₂ are connected to inner-tank liquiddischarge pipes 23 ₁ and 23 ₂ respectively. The liquid discharge pipe 23₁ is connected to a drain processing facility 40 through an on-offvalve, the pump, and the flow control valve. Similarly the liquiddischarge pipe 23 ₂ is connected to an exhaust processing facility 41through the on-off valve, the pump, and the flow control valve. The sink29 is also connected to the exhaust processing facility 41 ₁. The drainpipe 25 ₁ is connected to the lower position of the outer tank 25, andthe drain pipe 25 ₁ is connected to the liquid discharge pipe 23 ₁.

The vapor supply mechanism 37 is provided near the processing tank 15.The vapor supply mechanism 37 includes a vapor generation unit 37 ₁. Thevapor generation unit 37 ₁ reserves the organic solvent such as theisopropyl alcohol (IPA) solvent. The organic solvent such as the IPAsolvent easily mixes with the water remaining on and adhering to thesurface of the wafer W, and this organic solvent has extremely littlesurface tension. The vapor generation unit 37 ₁ heats the organicsolvent to vaporize it. The vapor generation unit 37 ₁ is dipped in hotwater in a heating tank 37 ₂, and the organic solvent is heated andvaporized. The vapor generation unit 37 ₁ and the organic solvent (IPA)supply source 36 are connected to each-other by piping 36 i, and IPA issupplied to the vapor generation unit 37 ₁.

The vapor generation unit 37 ₁ and a second nitrogen gas N₂ supplysource 35 are connected by branch piping 35 ₁₁ and branch piping 35 ₁₂.The nitrogen gas N₂ is supplied from the branch piping 35 ₁₂ to thebottom region of the vapor generation tank 37 ₁ to generate bubbles inIPA reserved in the vapor generation tank 37 ₁, which acceleratesevaporation of IPA. The nitrogen gas N₂ supplied from the branch piping35 ₁₁ is utilized as a carrier gas. The vapor generation tank 37 ₁ iscoupled to piping 34 ₂ through piping 37 ₁₂, and the mixed gas of thecarrier gas N₂ and the IPA vapor are supplied from the vapor generationtank 37 ₁ to the jet nozzles 33. A first nitrogen gas N₂ supply source34 supplies the nitrogen gas N₂ to the jet nozzles 33 through piping 34₁ and piping 34 ₂. The nitrogen gas N₂ supplied from the first nitrogengas N₂ supply source 34 is used not only for purging the inside of theprocessing tank 15 but also for finish drying.

Next the series of processes the substrate processing device will bedescribed with reference to FIG. 6 and FIG. 7. FIG. 6 shows a timingchart for the series of processes. FIG. 7 shows the washing and dryingprocess, FIG. 7(a) is a sectional view explaining the washing process,FIG. 7(b) is a sectional view explaining the drying process 1, FIG. 7(c)is a sectional view explaining the drying process 2, and FIG. 7(d) is asectional view explaining the drying process 3.

Referring to FIGS. 1 and 6, first the lid 30 of the processing tank 15is opened, and the assembly of wafers W′ is accommodated in the innertank 20. At this point, the desired chemical solution, e.g.,hydrofluoric acid (HF) is supplied to the inner tank 20 from thechemical solution supply source 39 through the pipe 22 ₁, whichintroduces the processing solution, and the processing solution supplyunit 22, and the desired chemical solution is reserved in the inner tank20. Therefore, the processing (for example, etching, hydrofluoric-acidtreatment, and washing, etc.) is performed on the assembly of wafers W′according to which chemical solution is used by dipping the assembly ofwafers W′ in the processing solution.

After the chemical-solution processing is finished, as shown in FIG.7(a), pure water DIW is supplied to the inner tank 20 from the purewater supply source 38 through pipe 22 ₁ which introduces the processingsolution, and the processing solution supply unit 22. The pure water DIWis supplied while overflowing from the upper region of the inner tank20. The pure water DIW overflowing from the inner tank 20 flows into theouter tank 25, and the pure water DIW is discharged from the drain pipe25 ₁ through the water discharge pipe. The pure water is supplied for arelatively long time to wash out the chemical solution HF which remainsin the inner tank 20.

After the washing process, in the drying process 1 shown in FIG. 7(b),the continuous supply of the pure water DIW is stopped, and the assemblyof wafers W′ is slowly raised from the inner tank 20 (rate is reduced)while a small amount of pure water is supplied (DIW water-saving). Asmall amount of IPA vapor can also be supplied into the processing tank15 at the same time as when the assembly of wafers W′ is raised.

Then, during the drying process 2 shown in FIG. 7(c), the drainmechanism valve of the outlet 21 ₂ in the bottom region of theprocessing tank 15 is operated to rapidly discharge the processingsolution, and the porous plate 28 is inserted between the inner andouter tanks 20 and 25 and the intermediate connecting member 26 byhorizontally moving the porous plate 28 into the frame body 27 ₁.Subsequently, the mixed gas of hot nitrogen gas N₂ and the IPA vapor issupplied to the inner tank 20. These operations are performedsimultaneously as shown in the timing chart. The nitrogen gas N₂ isheated in the vapor generating tank 37 ₁. In the drying process 2, theorganic solvent vapor in the processing tank 15 comes into contact-withthe surface of each wafer W, and the organic solvent vapor is condensedonto the surface of the wafer W to form a film of the organic solvent.When the organic solvent film is formed on the surface of the wafer W,the organic solvent is substituted for the pure water adhering to thewafer W. Therefore, the pure water flows out from the surface of thewafer W. In the drying process 3 shown in FIG. 7(d), the nitrogen gas N₂is supplied in order to dry the substituted IPA, and the assembly ofwafers W′ is taken out from the processing tank 15 when the dryingprocess 3 is finished.

When the flow of the drying gas in the drying process 2 in the abovedrying processes 1 to 3 is investigated, the route shown in FIG. 8 isobserved. FIG. 8 is a sectional view schematically showing the flow ofthe drying gas in FIG. 7(c). The drying gas (IPA+hot N₂) is jetted fromthe jet nozzles 33 in the upper region of the lid 30 to the assembly ofwafers W′. At this point, a clearance x is formed between the inner tank20 and the lid 30. A completely closed state is not formed between theinner tank 20 and the lid 30, but a half-closed state is formed betweenthe inner tank 20 and the lid 30 by the clearance x, i.e., a half-closedstate is formed between drying section and the washing section.Therefore, some of the drying gas jetted to the assembly of wafers W′flows into the sink 29 from the clearance x between the inner tank 20and the lid 30.

Further, since the processing tank 15 is placed in the air-conditionedhousing chamber 11, air 12 a is blown downward from the air conditioner12 in the upper region of the housing chamber 11 as shown by the arrows.As a result, the drying gas emitted from the clearance x is partiallyexhausted through the piping 22 ₂, and the remainder of the drying gasflows into the sink 29 along with the air 12 a and exhausted by anexhaust device coupled to the sink 29. Since the drying gas jetted fromthe jet nozzles 33 is emitted through the clearance x, the amount of gasflowing into the inner-tank 20 is decreased by the gas emitted throughthe clearance x. The amount of gas emitted through the clearance xbecomes relatively large. Therefore, the drying gas can be exhaustedwithout the influence of the fluctuation in evacuating station in theexhaust processing facility.

That is, after the drying gas is jetted on the assembly of wafers W′,some of the drying gas is emitted into the sink 29 through the clearancex, so that the amount of gas flowing in the inner tank 20 is decreasedby the amount of gas emitted into the sink 29. Therefore, even if afluctuation in the evacuating station exists, the drying gas cansmoothly be evacuated while the fluctuation does not largely have aninfluence. More particularly, when the clearance x is provided, thefluctuation in the evacuating station is absorbed by the larger spaceincluding not only the inner tank and the outer tank but also the sink,which allows the influence of the fluctuation in evacuating station tobe decreased compared with the case of a narrower space including onlythe inner tank and the outer tank. Further, since a large amount ofclean air is supplied from the upper region of the housing chamber 11,the fluctuation in the evacuating station can further be decreased.

On the other hand, since plural small holes have been made in the bodyof the porous plate 28, the drying gas passing through the porous plate28 is dispersed by the plural small holes, and a pressure difference isgenerated by the orifice effect between the lid 30 and the inner tank20, i.e., between the lid constituting the drying chamber and the innertank constituting the washing chamber. The drying gas in the dryingchamber is evacuated while flowing smoothly down. Therefore, thepressure of the lid 30 (drying section) becomes securely higher than thepressure of the inner tank 20 (washing section).

In this state, when a pressure relationship is shown between theprocessing tank 15 and the sink 29, the following relationships hold:

P₁>P₂>P₃>pressure of evacuating station, and

P₁>P₄>pressure of evacuating station.

Where P₁ is the pressure of the lid 30 (drying section), P₂ is thepressure in the inner tank 20, P₃ is the pressure in the exhaust pipe,and P₄ is the pressure in the sink 29.

Accordingly, when the pressures in the processing tank 15 and the sink29 satisfy the above relationships, the drying gas demonstrates alaminar flow in the processing tank 15, and the drying gas is smoothlyexhausted to the outside of the tank through the exhaust pipe. Throughthis process, the drying gas is uniformly supplied to each individualwafer, no water mark is formed on the substrate surface, any particlescan be removed, and the adhesion of particles can be also prevented.Further, the re-adhesion of particles can be suppressed because thedrying gas is not circulated in the processing tank.

1. A substrate processing method characterized by including: dividing aprocessing tank into a washing section and a drying section; forming aclearance in a joint between the washing section and the drying section;communicating the clearance with a sink; moving a substrate from thewashing section to the drying section in drying the substrate; insertinga porous plate into the lower region where a clearance is formed; andjetting a drying gas against the substrate with the internal pressure ofthe drying section kept higher than that of the sink and the internalpressure of the washing section kept lower than that of the dryingsection.
 2. The substrate processing method according to claim 1,characterized in that a processing solution supply unit and a processingsolution discharge unit are independently provided in the bottom regionof said washing section, and the following processes (a) to (d) areperformed in washing the substrate; (a) a process of supplying achemical solution from the processing solution supply unit into saidprocessing tank to reserve the chemical solution in the processing tank,(b) a process of inputting and dipping said substrate in the processingtank to perform chemical-solution processing to the substrate for apredetermined time; (c) a process of supplying a washing solution fromthe processing solution supply unit after the chemical-solutionprocessing is finished, and of discharging the chemical solution fromthe processing tank through the processing solution discharge unit; and(d) a process of stopping the supply of the washing solution after thechemical solution has been discharged.
 3. The substrate processingmethod according to claim 2, characterized in that a drain mechanism isprovided in said processing solution discharge unit, and in drying thesubstrate, the processing solution in said washing section is dischargedfor a short time by operating the drain mechanism at the same time as aporous plate is inserted between said washing section and said dryingsection.
 4. The substrate processing method according to claim 1,characterized in that said porous plate is a punched plate in which aplurality of small holes having a predetermined diameter are punched. 5.A substrate processing device which includes: a support means forsupporting a plurality of substrates to be processed at equal pitches inparallel and vertical orientation; a washing processing tank whichaccommodates an assembly of substrates supported by the support means;and a lid with which the upper opening of the washing processing tank iscovered, the lid also functioning as a drying processing tank, thesubstrate processing device characterized in that the lid includes acontainer having a size in which the assembly of substrates can beaccommodated, the top surface of the container being closed and a lowerregion of the container being opened, a plurality of jet nozzles arearranged in a matrix shape at substantially equal intervals in the topsurface of the container while respective jet-nozzle holes areorientated toward the assembly of substrates, and when the upper openingof the washing processing tank is covered with the lid, a clearancecommunicated with a sink is formed between the washing processing tankand the lid, and the porous plate is inserted into the lower region ofthe clearance.
 6. The substrate processing device according to claim 5,characterized in that said washing processing tank includes: aprocessing solution discharge unit and a processing solution supply unitwhich are independently provided in the bottom region of the washingprocessing tank; processing solution supply system piping which isconnected to the processing solution supply unit to supply theprocessing solution to the processing tank; a chemical solution supplysource which supplies the chemical solution to the processing solutionsupply system piping; washing solution supply means for supplying thewashing solution to the processing tank through the processing solutionsupply system piping, the washing solution supply means for washing thesubstrate by causing the washing solution to overflow from the upperregion of the processing tank; and discharge piping which is connectedto the processing solution discharge unit to introduce the washingsolution, discharged from the processing tank, to the outside of theprocessing tank.
 7. The substrate processing device according to claims5 or 6, characterized in that a drain mechanism is provided in saidprocessing solution discharge unit, and in drying said assembly ofsubstrates, the drain mechanism is operated at the same time as whensaid porous plate is inserted between said washing processing tank andsaid lid.
 8. The substrate processing device according to claim 5,characterized in that said plurality of jet nozzles are provided in thetop surface of said container along the outer circumference of saidassembly of substrates such that distances between the outercircumference and respective nozzle holes become substantially equal toone another.
 9. The substrate processing device according to claim 5,characterized in that said porous plate includes a punched plate with aplurality of holes having predetermined diameters.